#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, char* argv[])
{
    if(argc != 2) exit(1);
    //int fd = open("log.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //int fd = open("log.txt", O_CREAT | O_WRONLY | O_APPEND, 0666);
    int fd = open(argv[1], O_RDONLY);
    if(fd < 0) exit(1);

    dup2(fd, 0);
    close(fd);

    while(1)
    {
        char buffer[64];
        memset(buffer, 0, sizeof(buffer));
        if(!fgets(buffer, sizeof(buffer)-1, stdin)) break;
        printf("%s", buffer);
    }

    //printf("fd: %d\n", fd);
    //printf("hello linux\n");
    //printf("hello linux\n");
    //printf("hello linux\n");
    //fprintf(stdout, "hello stdout\n");
    //fprintf(stdout, "hello stdout\n");
    //fprintf(stdout, "hello stdout\n");
    //fprintf(stdout, "hello stdout\n");
    //fprintf(stdout, "hello stdout\n");

    //const char* msg = "hello world\n";
    //write(fd, msg, strlen(msg));

    //printf("stdin: %d\n", stdin->_fileno);
    //printf("stdout: %d\n", stdout->_fileno);
    //printf("stderr: %d\n", stderr->_fileno);

    //umask(0);
    //int fd1 = open("log1.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //int fd2 = open("log2.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //int fd3 = open("log3.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //int fd4 = open("log4.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //if(fd1 < 0) exit(1);
    //if(fd2 < 0) exit(1);
    //if(fd3 < 0) exit(1);
    //if(fd4 < 0) exit(1);

    //printf("fd1: %d\n", fd1);
    //printf("fd2: %d\n", fd2);
    //printf("fd3: %d\n", fd3);
    //printf("fd4: %d\n", fd4);

    //close(fd1);
    //close(fd2);
    //close(fd3);
    //close(fd4);

    //int fd = open("log.txt", O_CREAT | O_WRONLY | O_TRUNC, 0666);
    //int fd = open("log.txt", O_CREAT | O_WRONLY | O_APPEND, 0666);
    //int fd = open("log.txt", O_RDONLY);
    //if(fd < 0)
    //{
    //    perror("open");
    //    return 1;
    //}
    //printf("fd: %d\n", fd);

    //while(1)
    //{
    //    char buffer[64];
    //    int n = read(fd, buffer, sizeof(buffer)-1);
    //    if(n > 0)
    //    {
    //        buffer[n] = 0;
    //        printf("%s", buffer);
    //    }
    //    else if(n == 0)
    //    {
    //        break;
    //    }
    //}

    //const char* msg = "abcd";
    //int cnt = 1;
    //int a = 1234567;
    //while(cnt--)
    //{
    //    char buffer[16];
    //    snprintf(buffer, sizeof(buffer), "%d", a);
    //    write(fd, buffer, strlen(buffer));
    //}

    //close(fd);
    return 0;
}
